In early March 2010, the Decadal Survey Giant Planets Panel (GPP) requested a short-turnaround study to evaluate the feasibility of a small fission power system (FPS) for future unspecified National Aeronautics and Space Administration (NASA) science missions. FPS technology was considered a potential option for power levels that might not be achievable with radioisotope power systems. A study plan was generated, and a joint NASA/Department of Energy (DOE) study team was formed. The team developed a set of notional requirements, which were accepted by the GPP and which included 1 kW electrical output, 15-year design life, and 2020 launch availability. After completing a short round of concept screening studies, the team selected a single concept for further study and analysis. The selected concept is a uraniummolybdenum fueled, heat pipe cooled reactor with distributed thermoelectric power converters coupled directly to aluminum radiator fins. The team generated a preliminary configuration, mass summary, development schedule, and cost estimate. The system mass is 772 kg (including margin) and the rough order-of-magnitude cost for the 10-year flight system development program is $690M. The study results were presented at a preliminary review on April 8 to NASA and DOE management with no significant modifications requested. The final review with the GPP was held on April 16, 2010.